DX11 was introduced in CoP, not CS. As for LA having DX11, I don't think that would be possible at least in their timeframe. Completely changing the API runtimes? Either way, DX10 in CS and DX11 in CoP make really no difference in visual quality. They're last minute addons, just about all of the graphics features are also used in DX9. CoP in DX11 mode just has some minor tessellation on gas mask filters, and lighting is supposed to be different but looks the same.

Expect LA to be DX9, if you're going to have any expectations at all. Just know that this wouldn't mean it's outdated in comparison to any game in recent years, which are all essentially DX9, some just have last minute, non-noticeable DX11 addons. The first true DX11 game looks to be Crysis 3, which comes out next year.

None of those use real DX11 effects at all. Not in the lighting system, not in the form of tessellation, none. BF3's best DX11 effect is the multithread support. Metro 2033's is... nothing. It might use tessellation to a very minor (unnoticeable, negligible) extent like CoP. Crysis has a better lighting system and post processing than Metro 2033, and also has better technical graphics than BF3. The first real DX11 game will be Crysis 3.